A conventional optical device with a micro-lens is fabricated to form the lens by employing selective meltback etching and regrowth techniques. FIG. 1 is a cross-sectional view showing the structure of the conventional optical device fabricated by employing the aforementioned techniques. The optical device is fabricated by a process which comprises the steps of: forming an etching mask on a single crystal substrate (4), performing meltback etching on the substrate, growing a thin layer to give a micro-lens (1) by regrowth technique, and evaporating an electrode (2) for ohmic contact.
However, the optical device fabricated by the prior art process has revealed some drawbacks in a sense that a tall and uneven ridge (3) ranging 10 micro meter to 30 micro meter in height is essentially created in the course of regrowing the thin layer, which makes it difficult not only to array a plurality of the optical devices in a single substrate as well as to integrate the optical devices with the other devices in a subsequent step.